How robots and humans can safely share public spaces

Human navigation relies heavily on social cues and negotiation. We instinctively move aside for someone on crutches, clear paths for emergency responders and navigate around each other through subtle body language and eye contact. Robots currently lack these communication channels, creating a fundamental challenge: How can robots operating in public areas convey its priority status to surrounding humans?

Robots operating in public areas are known as public-area mobile robots (PMRs). As they increasingly populate our sidewalks, hospital corridors and airport terminals, society faces a quandary: How should we determine rights-of-way for machines operating in human spaces?

The current default approach – robots always give priority to humans except when crossing roadways as pedestrians – is inadequate when considering the spectrum of robotic applications emerging in public spaces.

Today's conversation about sidewalk robots typically centres on delivery devices carrying packages or food. Consider the automated wheelchair navigating an airport terminal with a passenger who lacks navigational control. Should this device possess the same priority as a manual wheelchair? The answer seems intuitively yes, but implementation raises thorny questions about algorithmic decision-making and enforcement.

The complexity deepens when we examine PMRs serving critical functions. A robot rushing emergency medical supplies to a cardiac patient may not be able to wait. A robotic guide dog assisting a blind pedestrian requires certain navigational privileges to ensure its user's safety. A police-assist robot responding to a security incident may need priority passage through crowded spaces. Each scenario demands a nuanced understanding of rights-of-way that transcends the simplistic "robots always give priority" paradigm.

Traditional road vehicles highlight priority with sirens and flashing lights. Imagine delivery robots using sirens or loud sounds while navigating a neighbourhood – the cacophony would be unbearable. Yet without clear signals, how would pedestrians know that a particular robot carries time-critical cargo rather than someone's lunch?

This communication challenge demands innovative solutions. Perhaps priority robots could employ distinctive visual markers – specific colour patterns or symbol displays that become universally recognized.

Subtle audio cues, like the gentle chirping of pedestrian crossing signals, might indicate approaching priority PMRs without creating noise pollution. Smartphone apps could alert nearby pedestrians with vision or hearing difficulties that a high-priority robot is nearby. Perhaps haptic signals will be helpful. Whatever solutions emerge must balance effectiveness with the need to maintain livable public spaces.

Programming rights-of-way into robotic systems requires translating fluid social negotiations into rigid algorithmic decisions. A robot's navigation system must evaluate countless variables: Is that approaching human elderly or disabled? Is the robot's cargo time-sensitive? Are alternative routes available? How crowded is the current path?

The algorithms governing PMR behaviour must also account for edge cases and ethical dilemmas. Should a medical supply robot risk passing very close to a pedestrian if re-routing would critically delay delivery? How should robots prioritize when encountering other robots – should a first-come, first-served approach apply, or should cargo criticality determine precedence?

These questions have both ethical and livability issues as well as practical implications for system designers.

As PMR populations grow, robot-to-robot interactions will become increasingly common. Unlike human-robot encounters, these interactions could theoretically operate through direct digital communication, enabling instantaneous negotiation of passage rights. A standardized protocol might allow robots to broadcast their priority levels, destinations and cargo types, facilitating efficient traffic flow.

However, this digital negotiation system raises concerns about gaming and abuse. What prevents a logistics company from programming its robots to exaggerate their priority? How can a traffic authority verify that a robot claiming to carry medical supplies actually does?

Any rights-of-way framework must prioritize equity and accessibility. The disability community, already navigating challenging public spaces, should not bear additional burdens from robotic systems. Automated wheelchairs and guide robots should enjoy equivalent rights to their current counterparts. Communities must have meaningful input into how PMRs operate in their spaces, preventing scenarios where technological deployments outpace social acceptance.

Socioeconomic equity also demands consideration. Will priority robot services be available only to those who can afford premium services? How do we prevent a two-tiered system where the wealthy bypass pedestrian congestion through priority robotic services while others wait? These questions require proactive policy development rather than reactive regulation.

Addressing PMR rights-of-way requires near-term attention, even though widespread deployment remains in the future. Waiting until critical incidents occur – until someone suffers because a medical or other critical service robot couldn't navigate a crowd – would represent a failure of foresight.

Initial phases might focus on establishing communication standards and testing priority signaling methods in limited deployments. Airport terminals and hospital campuses could serve as testing grounds where controlled populations can provide feedback on different approaches. These early experiments should explicitly include disability advocates, urban planners, ethicists and affected communities in their design and evaluation.

Subsequent phases could expand to broader public spaces while refining protocols based on real-world experience. Regulatory frameworks must remain flexible enough to accommodate technological advancement while maintaining safety standards. International coordination will prove essential, as PMRs and their programming will likely cross jurisdictional boundaries.

The question of PMR rights-of-way represents more than a technical challenge – it's a fundamental reimagining of how we share public spaces with autonomous systems.

Success requires acknowledging the complexity of these interactions while committing to inclusive, iterative solutions. We must resist the temptation to impose simplistic rules that fail to account for the diverse roles PMRs will play in our communities.

Starting this conversation now, before widespread deployment, offers the opportunity to shape technology that serves human needs rather than forcing humans to adapt to technological limitations. Through thoughtful planning, community engagement and iteration based on experience, we can create a framework that ensures PMRs enhance rather than complicate our shared spaces.

The alternative – waiting until problems become critical – risks both human safety and the potential benefits these technologies could provide. The time for action is now, before the first preventable tragedy.